Recent progresses on the development of thioxo-naphthalimides

Thioxo/dithioxo-naphthalimide is a class of rarely visited fluorophore, first synthesized in 1999. Facile chemistry was devised to achieve mono or dual thionation of the two carbonyl groups of 1,8-naphthalimide. Thionation effectively shifts absorption maximum to longer spectral wavelength, significantly increase absorption coefficients, and dramatically enhances intersystem crossing efficiency with respect to their oxo-analogues. They were first explored as potent photocleavers to induce DNA strand break and novel photosensitizers for photodynamic therapies. In recent years, the unique chemistry of thioxo groups has been harnessed to achieve new applications, such as fluorescent sensors for heave metal ions. These unique photochemical and photophysical characteristics revitalize them intriguing functional molecules to investigate. In this short review, we wish to revisit their first discovery, facile synthesis, and the endeavors on the use of thioxo/dithioxo-naphthalimides for novel chemical and biomedical applications.     

Conducting polymer engineered covalent organic framework as a novel electrochemical amplifier for ultrasensitive detection of acetaminophen

Two-dimensional covalent organic framework(COF) has distinctive properties that offer potential opportunities for developing advanced electrode materials.In this work,a core-shell material composed of TAPB-DMTP-COF(TAPB,1,3,5-tris(4-aminophenyl)benzene;DMTP,2,5-dimethoxyterephaldehyde)core and conducting polymer shell,TAPB-DMTP-COF@PANI,was synthesized solvothermally using a polymerization method.The structural cha racteristics of the prepared composite were revealed by X-ray diffraction patterns(XRD),fourier transform infrared spectra(FTIR),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM).The electrochemical analyses were verified by subsequent monitoring of trace levels of acetaminophen.This resultant composite not only facilitated acetaminophen to interact with absorption sites by π-π stacking effect and hydrogen bonding but also overcame the poor conductivity of COF.Under the optimal conditions,a low limit of detection of0.032 μmol/L and wide linear range of 0.10-500 μmol/L were obtained.The electrochemical platform was almost unaffected by other interfering substances,and successfully applied for the practical detection of acetaminophen in commercial tablet,human blood serum and urine.The enhanced performance makes this COF based core-shell composite a promising material in electrochemical senso r.     

利用手持技术数字化实验测定中和反应化学计量比*

化学计量比在中学教学及实际生产中有着重要应用,本研究针对化学计量比概念教学存在的不足,以手持技术TQVC概念认知模型为理论依据,设计实验测定中和反应的化学计量比。基于等摩尔连续变化法,本实验借助温度传感器测定不同物质的量之比反应物反应后的温度变化数据,找出最大温度变化差值对应的反应物物质的量之比,即化学计量比,帮助学生从定量的角度理解化学计量比概念。     

A Novel Non-enzymatic Selective and Sensitive Glucose Sensor Based on Nickel-Copper Oxide@3D-rGO/MWCNTs

In this work, a modified 3D-rGO/MWCNT with nickel and copper oxide nanoparticles were synthesized. The structural properties of this nanocomposite were investigated by several techniques. The fabricated sensor at optimum condition potential of +0.60 V (vs. Ag/AgCl) and a rotational rate of 1800 rpm gave a detection limit of 0.04 μmol L⁻¹ with two dynamic ranges of 0.10–300 and 300–900 μmol L⁻¹ glucose with high stability. The good accuracy of the fabricated sensor was proved in the determination of glucose in a blood sample (with recoveries between 95 % to 105 % and RSDs of 1.2 to 2.5 %).     

Performance Improvement of Acid Pretreated 3D-printing Composite for the Heavy Metal Ions Analysis

The performance enhancement of 3D-printed electrode comprised of polylactic acid (PLA) and graphite (Gr) doped with graphene oxide (GO) was studied to detect five heavy metal ions in trace level. The pretreatment of PLA/Gr/GO electrode with potential cycling in H₂SO₄ solution achieved the most sensitive response. The characteristics of the composite electrodes were verified using XPS, FE-SEM, EDXS, Raman, and impedance spectroscopy. The experimental variables affecting the response current were optimized with respect to pH, deposition time, ratio of PLA/Gr/GO, and supporting electrolytes. The pretreated 3D-PLA/Gr/GO electrode showed a wide dynamic range from 0.5 ppb to 1.0 ppm with low detection limits of 0.039–0.13 ppb. The reliability of the PLA/Gr/GO electrode was evaluated by analyzing the reference samples of European Reference Materials.     

尿液pH变化与尿液中纳米微晶组分的关系

采用X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)研究了尿液pH变化与尿液中纳米微晶组分的关系。不但尿pH差异大的不同人尿液中微晶组分存在差异,而且同一人的尿pH发生变化时,其尿微晶亦发生变化。尿pH值较低(如pH＜5.8)时,主要为尿酸、酸式磷酸盐和草酸钙等;尿pH值较高(如pH＞6.2)时,主要为尿酸盐、磷酸盐、磷酸铵镁和草酸钙等。联合运用XRD和FTIR两种方法,可以更好地检测尿液中晶体组分,有助于了解尿石症的成因。     

基于气体浓度定量的嗅觉刺激器优化设计

现有的基于磁共振测量的嗅觉刺激器,通过调节嗅剂液体浓度的方法可以实现不同浓度的嗅觉刺激,但随着实验进行,受到嗅剂挥发以及实验环境（温度、湿度、气流量）变化的影响,很难确保输送至鼻腔的嗅剂气体浓度的稳定性,进而影响实验结果的准确性．本研究对本实验室前期开发的嗅觉刺激装置进行改进,实现了气体浓度精确定量．改进后的嗅觉刺激器主要分为三个部分：控制系统、反馈系统和气路系统．控制系统主要实现气路系统的送气控制和嗅剂气体浓度调节;反馈系统则负责对气体浓度进行测量;气路系统则在原有基础上添加活性炭装置,降低无关因素干扰．装置改进之后,不同气路切换时间为75.2 ms,比原装置减少了1 s,有效提高刺激精度．实验结果显示,气体浓度调节前,300 s内乙醇、吡啶、乙酸戊酯嗅剂气体浓度分别下降6.7%、71.4%、79.2%,嗅剂气体浓度短时间内发生较大改变．加入气体浓度调节功能后,当气体浓度下降至目标浓度的90%时,可通过调节气泵电压改变嗅剂气流与空气气流比例,从而调节嗅剂气体浓度至目标值,其中吡啶、乙酸戊酯用时13 s．     

聚吡咯纳米线凝胶的模板制备及储能与电化学传感性能

以配位聚合物凝胶为模板,构筑均一的聚吡咯纳米线网络,聚合后经简单处理除去模板,得到性能优异的聚吡咯凝胶.结果表明,模板法合成的聚吡咯凝胶为由均一纳米线组成的三维网络结构,具有良好的力学性能、较大的比表面积及优异的电化学特性,在0.28 A/g电流密度下,比电容可达450 F/g,在2.8 A/g电流密度下充放电1000次,比电容仍可保持88.6%.聚吡咯纳米线网络凝胶经葡萄糖氧化酶负载后得到柔性传感电极,对低浓度(0.2 mmol/L)的葡萄糖具有快速响应性能,有望用于超级电容器及生物电化学传感器等领域.     

基于铈配合物信号探针的凝血酶电化学适体传感器

以Ce³⁺为中心离子,N,N-二甲基甲酰胺(DMF)为有机配体,通过温度调节,合成系列形貌和电化学信号不同的铈配合物(Ce-COPs)。筛选出电化学信号最强的多面体状Ce-COP为信号探针。通过凝血酶(TB)与TB适体链之间的特异性识别作用,设计了一种简单通用的TB适体传感器。最优实验条件下,该传感器对TB的线性响应范围为1.0 fmol·L^-1~1.0 nmol·L^-1,检测限为0.94 fmol·L^-1。此外,本方案方法与商品人凝血酶(TM) ELISA试剂盒检测结果相近。结果表明,我们构建的TB适体传感器具有良好的灵敏度、特异性、选择性和稳定性。     

All-Polymer Piezo-Composites for Scalable Energy Harvesting and Sensing Devices

Silicone elastomer composites with piezoelectric properties, conferred by incorporated polyimide copolymers, with pressure sensors similar to human skin and kinetic energy harvester capabilities, were developed as thin film (<100 micron thick) layered architecture. They are based on polymer materials which can be produced in industrial amounts and are scalable for large areas (m²). The piezoelectric properties of the tested materials were determined using a dynamic mode of piezoelectric force microscopy. These composite materials bring together polydimethylsiloxane polymers with customized poly(siloxane-imide) copolymers (2–20 wt% relative to siloxanes), with siloxane segments inserted into the structure to ensure the compatibility of the components. The morphology of the materials as free-standing films was studied by SEM and AFM, revealing separated phases for higher polyimide concentration (10, 20 wt%). The composites show dielectric behavior with a low loss (<10⁻¹) and a relative permittivity superior (3–4) to pure siloxane within a 0.1–10⁶ Hz range. The composite in the form of a thin film can generate up to 750 mV under contact with a 30 g steel ball dropped from 10 cm high. This capability to convert a pressure signal into a direct current for the tested device has potential for applications in self-powered sensors and kinetic energy-harvesting applications. Furthermore, the materials preserve the known electromechanical properties of pure polysiloxane, with lateral strain actuation values of up to 6.2% at 28.9 V/μm.